Narrative:

I taxied out of taxiway then left onto another taxiway following the airport diagram. The txwys and runways were snow packed. I then taxied southeast into the sun; which was occasionally breaking through freezing fog. I was holding short of what I thought was runway 7L. I called the tower and checked in just as the tower cleared a B747 to land runway 7L; the same runway I was to depart from at the intersection. The tower cleared me for an immediate takeoff. Between the snow on the ground; ice-fog; the sunlight; deice fluid on the windshield; and the rush due to traffic; I started to roll from the intersection on the taxiway. Taxiway parallels runway 7L. I then heard the tower call that I was on the taxiway not the runway. I immediately went to idle power and maximum braking to stop the aircraft. The tower then told me to hold short of runway 7L at taxiway and I proceeded there until I was cleared for takeoff. I then departed for a normal flight. Contributing factors: 1) packed snow on txwys and runways. 2) runway and taxiway lighting obscured by snow and frost. 3) poor forward visibility through windshield due to deice fluid. 4) RVR was approximately 2800 ft in that area. 5) morning sun glaring off ice-fog. Pilot errors: 1) did not adequately clean windshield of deice fluid. 2) assumed that I was in the proper position and did not confirm this with signs and light that were not covered with snow and frost; lost situational awareness. 3) allowed myself to be rushed.

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Original NASA ASRS Text

Title: C208 PLT INADVERTENTLY ATTEMPTS TO TAKE OFF ON THE TXWY. CTLR ISSUES AN ALERT TO STOP.

Narrative: I TAXIED OUT OF TXWY THEN L ONTO ANOTHER TXWY FOLLOWING THE ARPT DIAGRAM. THE TXWYS AND RWYS WERE SNOW PACKED. I THEN TAXIED SE INTO THE SUN; WHICH WAS OCCASIONALLY BREAKING THROUGH FREEZING FOG. I WAS HOLDING SHORT OF WHAT I THOUGHT WAS RWY 7L. I CALLED THE TWR AND CHKED IN JUST AS THE TWR CLRED A B747 TO LAND RWY 7L; THE SAME RWY I WAS TO DEPART FROM AT THE INTXN. THE TWR CLRED ME FOR AN IMMEDIATE TKOF. BTWN THE SNOW ON THE GND; ICE-FOG; THE SUNLIGHT; DEICE FLUID ON THE WINDSHIELD; AND THE RUSH DUE TO TFC; I STARTED TO ROLL FROM THE INTXN ON THE TXWY. TXWY PARALLELS RWY 7L. I THEN HEARD THE TWR CALL THAT I WAS ON THE TXWY NOT THE RWY. I IMMEDIATELY WENT TO IDLE PWR AND MAX BRAKING TO STOP THE ACFT. THE TWR THEN TOLD ME TO HOLD SHORT OF RWY 7L AT TXWY AND I PROCEEDED THERE UNTIL I WAS CLRED FOR TKOF. I THEN DEPARTED FOR A NORMAL FLT. CONTRIBUTING FACTORS: 1) PACKED SNOW ON TXWYS AND RWYS. 2) RWY AND TXWY LIGHTING OBSCURED BY SNOW AND FROST. 3) POOR FORWARD VISIBILITY THROUGH WINDSHIELD DUE TO DEICE FLUID. 4) RVR WAS APPROX 2800 FT IN THAT AREA. 5) MORNING SUN GLARING OFF ICE-FOG. PLT ERRORS: 1) DID NOT ADEQUATELY CLEAN WINDSHIELD OF DEICE FLUID. 2) ASSUMED THAT I WAS IN THE PROPER POS AND DID NOT CONFIRM THIS WITH SIGNS AND LIGHT THAT WERE NOT COVERED WITH SNOW AND FROST; LOST SITUATIONAL AWARENESS. 3) ALLOWED MYSELF TO BE RUSHED.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.